Rocky...was this with the 40mm Angel Eyes? I have seen good result with these COB ringlights. Turns out the 50 mm has about 40mm ID, so mounts nicely onto a 40.5mm-52mm step-up adapter. Here's what it looks like:

The bulge in the shrink wrap is a limiting resistor. I plan to install a 12V jack but haven't decided on the right resistor value yet to get best brightness and color temp.

yes ray this is the light. Ray good idea put a resistor in the circuit. push the load through the light. that will definitely brighten the light. that is a good idea for sure. i may try that as well._________________Rocky Carter

Using resistor is a bit wasteful as it generates heat. Use an active, adjustable voltage regulator/DC-DC step up device is probably better and you do not need 12V, a box of 4 AA battery should be good. Here is what I did. I think that the DC-DC device regulates voltage well, so even the voltage of your AA batteries drops, the output voltage stay the same (unless batteries are really used up), thus you maintain constant brightness till batteries are dead._________________https://www.facebook.com/groups/mjkzzfs/

Using resistor is a bit wasteful as it generates heat. Use an active, adjustable voltage regulator/DC-DC step up device is probably better and you do not need 12V, a box of 4 AA battery should be good. Here is what I did. I think that the DC-DC device regulates voltage well, so even the voltage of your AA batteries drops, the output voltage stay the same (unless batteries are really used up), thus you maintain constant brightness till batteries are dead.

Yours is a better solution, but for one-off use the resistor works OK.

It would be nice to have a generic current source controller for these kind of projects.

Here is how i did my cobb angel eye. I purchased a AC to DC converter at amazon.ca 25.00 Canadian. The power supply is 12 volt 5 amp max. I went to a hardware store purchased a dimmer switch along with a switch box. I also purchased a cheap power bar. I cut the power cord in half on the power bar. wired the dimmer switch and mounted it in the switch box. This way i can dim the light to what i want. Depending on the metal of the coin. I am photographing. I wired every thing together. The dimmer switch is a dial dimmer work perfectly. I can now use this power supply for lots of things i need. With a dial dimmer it is graduated. That way i record the setting for the various types of coins. Works perfectly for myself._________________Rocky Carter

thanks ray, just hooked VCM up to an LED ring of mine, worked beautifully, though not sure if 4096 levels of power is needed, probably 64 is enough. Good thing is it does not flicker at low power setting as it does not use PWM.

How high voltage can I apply to the VCM? Not sure how much I will need but 12V is not enough. I run 25V with a dropping resistor and it works well. I think they run at rated current without resistor at 13.6V, so I will need to supply that.

How high voltage can I apply to the VCM? Not sure how much I will need but 12V is not enough. I run 25V with a dropping resistor and it works well. I think they run at rated current without resistor at 13.6V, so I will need to supply that.

yes ray that is right. These lights run at 13.6 to 13.7 volts constantly._________________Rocky Carter

I told them to put in caps made by Samsung and rated 50V, as I really do not trust Chinese made caps. The 7805 in the VCM can handle 30V.

Quote:

How high voltage can I apply to the VCM? Not sure how much I will need but 12V is not enough. I run 25V with a dropping resistor and it works well. I think they run at rated current without resistor at 13.6V, so I will need to supply that.

I think these Angels' eyes comes with a current limiting thing in metal casing, so I believe you should be able to drive it at 12V. I only needed about 8.3V for my mod with DC-DC step up setting to have enough light, even with a plastic cover. So if you use 25V, a lot of power is wasted as heat, probably more than 50%

The particular ring shown in video is arranged as 3 LEDs in series as a group, 10 groups and total of 30 LEDs. Each LED has forward voltage between 2.85V to 3V, so 12V should be enough for the VCM to drive it at full power_________________https://www.facebook.com/groups/mjkzzfs/

I thought i would try to find this thread. A couple of members and myself from another forum. Have been working on building a home made microscope. I will have mine complete very soon. Just waiting for some more glass to come. My friends are at the same place with with there microscopes. We are very sure they should work very well. Lin i know you are reading this. I should have my final pieces next week._________________Rocky Carter